Multicolumn listbox, large row selection is slow

[jzoller]

Not a critical bug, but it's costing me some redesign time. Maybe this can prevent others from having the same problem.

Found in Win2k, LV7.1. In a multicolumn listbox, selecting many (>500) rows at one time consumes the processor and makes LV unresponsive for large (minute+) periods of time. The more rows selected, the longer the processor is consumed for.

NI is aware of this issue.

Steps to reproduce:

1. Start a new, blank VI.

2. Place a Multicolumn Listbox on the front panel.

3. Change the selection mode on the Multicolumn Listbox to "1 or more".

4. Fill the listbox with > 500 rows via the "ItemNames" property. (mine was 15 elements wide as well)

5. Select the first row (VI running or not, or even in exe form, does not seem to matter).

6. Scroll down to the bottom of the control.

7. Hold down shift, and select the last row.

Possible workarounds:

-Don't use multicolumn listboxes: this behavior was not seen under single column listboxes.

-Only present a small number of rows in the listbox at a time, updating as necessary.

Good luck folks,

JZ

[Michael Aivaliotis]

Yes. I already reported this in LV7.0. I guess it still exists in 7.1... :thumbdown:

See my post:

http://forums.lavausergroup.org/index.php?showtopic=142

[jzoller]

Yes. I already reported this in LV7.0. I guess it still exists in 7.1... :thumbdown:

See my post:

http://forums.lavausergroup.org/index.php?showtopic=142

2616[/snapback]

Ah, should have known it was found if I had looked hard enough! It's a shame I had to waste time on this that could have been spared by a public, NI published bug list.

Thank you for finding it! Next time, I'll check both the 7.0 and 7.1 lists.

JZ

[Mike Ashe]

I ran into this a long time ago with MCLB. They look great, but sloowwwww.....

I ended up using a 2D string array (table now) with some tweaking in the custom control editor to add scroll bars and a couple of VIs to manage highlighting selections, etc, for cut/copy/paste in the table. Fast and efficient.

Cheers,